In connection with the recovery of hydrocarbons from the earth, wellbores are generally drilled using any of a variety of different methods and equipment. According to one common method, a drill bit is rotated against the subsurface formation to form the wellbore. The drill bit may be rotated in the wellbore through the rotation of a drill string attached to the drill bit and/or by the rotary force imparted to the drill bit by a subsurface drilling motor powered by the flow of drilling fluid down the drill string and through downhole motor.
The flow of drilling fluid can exhibit variations in pressure. These pressure variations can cause dimensional changes in solid structures such as piping that carries the drilling fluid to and from the drill string. Strain gauges are used for detection and measurement of absolute dimensional changes of solid structures, such a piping for drilling fluid, but such changes are generally very slow and difficult to observe with known equipment and measurement methods.